Preparation method of cassava modified starch

The invention discloses a preparation method of cassava modified starch, which comprises the following steps: weighing commercial cassava starch, adding a right amount of pure water to obtain starch milk, regulating the pH value of the reaction system to 10.50-11.50 with a sodium hydroxide solution, adding animal glue dissolved in warm water into the reaction system, and adding sodium hypochlorite into the glue in the reaction system, wherein the mass of the sodium hypochlorite is 8-10 times that of the glue; and reacting in a 30-35 DEG C thermostatic bath for 3.5-4.5 hours while controlling the reaction, regulating the pH value of the reaction system to 5.50-6.00 after the reaction is qualified, carrying out vacuum filtration, drying in an oven, pulverizing, and screening to obtain the finished product. The cassava starch is used as a raw material, and edible glue is used as a reaction crosslinking agent to prepare the cassava crosslinked starch, thereby enhancing the high viscosity, shear resistance and aci